Remember the film, "Outbreak," starring Dustin Hoffman? In 1989, in a quarantine facility in the town of Reston, Va., a lethal virus broke out among imported monkeys. America faced an outbreak of the highly contagious Ebola virus, which kills by massive internal hemorrhage and is capable of jumping from one species to another. It has been said that Ebola does in 10 days what HIV does in 10 years.

Back in 1918 the "Spanish Flu" virus killed up to 50 million people, and was recreated recently when a Canadian Laboratory rebuilt the virus and witnessed its awesome killing power first hand, when lungs of infected monkeys were destroyed in just days as their immune systems went into overdrive.

The reason for the lethal nature of the 1918 flu was never fully understood. But the experts behind this test say they have found a human gene which may help explain its unusual virulence.

Despite the large number of casualties at the time, doctor had no way to preserve tissue samples taken from infected patients, until recently, when the preserved body of a flu victim buried in Alaskan permafrost was exhumed, and they painstakingly extracted the genetic material needed to work out the structure of the virus.

In a maximum "biosafety" facility at Canada's National Microbiology Laboratory they reconstructed a fully functioning virus from the genetic material, and infected macaque monkeys to see what would happen.

Symptoms appeared within 24 hours of exposure to the virus, and the subsequent destruction of lung tissue was so widespread that, had the monkeys not been put to sleep a few days later, they would literally have drowned in their own blood.

The results are very similar to those described in human patients at the time the virus was at its peak in 1918.